Refrigerant compression unit



y 1933- I s. c. FRICKE 2,122,462

REFRIGERANT COMPRESSION UNIT Filed Oct. 12, 1936 3 Sheets-Sheet 1 INVENT OR. 61213 C, Bic/ Z6.

ATTORNEYS.

y 5, 1938. G. c. FRICKE 2,122,462

REFRIGERANT COMPRES SION UNIT Filed Oct. 12. 1936 3 Sheets-Sheet 2 INVENTOR. 626g 6, 356%6.

BY 7::4MM, M mam J4 ATTORNEYS'Z July 5, 1938. V

G. c. FRICKE 2,122,462

REFRIGERANT COMPRES SION UNIT Filed Oct. 12. 1936 3 Sheets-Sheet 3 W W W .lE'. A53? INVENTOR. ii 621 C Frz'c e.

ATTORNEYS.

Patented July 5, 1938 UNITED STATES PATENT OFFICE 2,122,462 REFRIGERANT commission UNIT Guy 0. Fricke, Pleasant Ridge, Mich. Application October 12, 1936, Serial No. 105,186

1 Claim.

The present application relates to pump constructions. More particularly it relates to a sealed type of pump primarily adapted for use as the compressing unit in a refrigeration system 5 and in which the pump as well as the motor for driving the same is completelysealed within an enclosing housing.

It is a primary object of the present invention ing an eccentric portion formed on the shaft. A

, valve ring is disposed in this cylinder which valve ring is positioned with respect to the cylinder by means of two diametrically opposed reciprocably mounted vanes which engage the surface of the valve ring. The valve ring is provided with an axially extending recess adapted to receive. the

rounded end of one of these vanes in order to effect rotation of the valve ring with the cylinder as the latter rotates.

It is an object of the present invention to provide a pump of the general type outlined above .in which the central axially disposed shaft about 7 which the various rotary parts of the pump move, is supported at both its upper and lower ends and the rotatable parts of the apparatus are journaled on this shaft between its ends. Consequently when one end of the shaft is locked against rotation,.both ends provide a firm concentrically disposed. support for the rotary parts which are journaled upon the shaft.

Still further the present invention contem- I plates the provision of a sleeve secured to the motor, which sleeve is press fitted into the rotor in .order to. effect a tight non-rotatable connection therewith. The sleevels journalled onthe stationary centrally disposedshaftt This construction provides one which is extremely satisfactory and exceptionally simple to assemble.

Still further the present invention contemplates the provision of novel means for securing thec'ylihder construction to this sleeve, which means' -include axially disposed bolts extending along lines parallel to the axis of the cylinder,

which bolts pass axially through the cylinder walls and are threadably received by the sleeve which, as mentioned above, is secured to the rotor. This construction is found to provide one which facilitates the assembly of the parts and greatly simplifies the mountingv of the mechanism within the housing.

The invention further contemplates a novel construction and arrangement of parts in which various of the parts are manufactured from cast 10 iron while others are made from hard steel and in each instance the parts are so constructed and arranged that the relativelymovable members provide bearings between a cast iron member and a steel member in all instances in order that the 15 apparatus will be extremely long wearing and thus render adjustment thereof unnecessary after the device has been once completely assembled.

It is a further object of the invention to provide a pump of this general type in which the 20 eccentric parts of the pump which rotate during operation of the pump have relatively small mass in order that the eccentric mass of the pump as a whole will be greatly reduced thereby greatly minimizing wear on the" various parts, reducing 25 vibration, and contributing greatly to a quiet and smoothly operating unit. Another object of the present invention is to provide a pump construction of this general type embodying novel lubrication features, as a result 3oof which an ample supply of lubricant ismaintained adjacent all of the bearing surfacesof the pump construction as a whole, and the circulation of'such lubricant is maintained as the result of the rotation of the pump parts. 35

The oil system embodied in the present apparatus includes a plurality of downwardly projecting scoops which extend into a reservoir of oil maintained in the bottom of the housing or casing in which the pump construction is 40 mounted. These scoops, due to the rotation of the member in which they are mounted, serve to positively feed oil upwardly to a point adjacent the bearing of the rotor of the motor upon the upwardlyinto th'epump chamber from the lower 55 end thereof, thus providing a construction in which positive lubricant feed is provided into the pump chamber from both axial ends thereof, thereby insuring proper lubrication of all bearing surfaces.

Still another important feature of the present invention resides in the provision of a novel exhaust valve for the pump chamber in which a valve construction is provided which is easily and simply constructed, and installed and which is particularly efiective in operation.

The above enumerated objects are merely illustrative of certain features and desirable results inherently obtained by the structure of the apparatus described in detail below.

Many other and further objects, advantages, and features of the present invention will become clearly apparent from the following specificationwhen considered in connection with the accompanying drawings forming a part thereof.

In the drawings:

Figure 1 is a vertical sectional view taken through a pump showing one embodiment of the present invention and illustrating the'various parts in assembled relation.

Fig. 2 is a transverse sectional view taken substantially on the line 2-2 of'Fig. 1, illustrating in detail the cross sectional configuration of the pump cylinder, the valve ring, and the exhaust ports for the pump chamber showing the mounting of the valves therefor.

Fig. 3 is a transverse sectional view taken substantially on the line 3-3 of Fig. 1, illustrating in detail the cross-sectional configuration of the pump chamber and specifically the manner in which the valve ring is positioned therein by means of the radially reciprocable spring pressed vanes which serve to maintain the valve ring in predetermined position with respect to the cylinder with which it is associated.

Fig. 4 is a transverse sectional view similar to Fig. 3 illustrating the'cylinder after being rotated through 90 in order to more clearly illustrate the movement of the valve sleeve or ring with respect to the cylinder in which it is mounted and the eccentric upon which it is disposed.

Fig. 5 is an enlarged elevational view taken substantially on the line 5-5 of Fig. 2, illustrating in detail the mounting of one of the valve members for the exhaust portion of the cylinder.

Fig. 6 is a transverse sectional view taken substantially on the line 66 of Fig. 5 illustrating in detail the mounting of one of the valve mem bers serving to close one of the exhaust ports of the pump chamber.

Fig. '7 is a transverse sectional view taken substantially on the line 1-1 of Fig. 1 illustrating in detail the oil supply duct and the manner in which lubricant is conducted from the cylinder construction to the bearings around the centrally disposed supporting shaft.

Fig. 8 'is a vertical sectional view taken substantially on the line 8-8 of Fig. 7 illustrating in detail the lubricant duct-and the manner in which lubricant is conveyed from the lower portion of the casing to the central portion of the support shaft, and further the manner in which such lubricant is distributed throughout the axial length of the support shaft and to the pump chamber. 7

Fig. 9 is a" fragmentary transverse sectional view taken substantially on the line 0-4 of Fig. 1 illustrating in detail the manner in which all is picked up at the lower end of the stationary shaft and fed upwardly to the pumping cylinder.

Fig. 10 is a fragmentary transverse sectional view taken substantially on the line Iii-i0 of Fig. 1 illustrating in detail the manner in which the cap at the lower end of the cylinder is secured in position and the relative disposition of the ports which serves to pick up and distribute the supply of oil to the apparatus.

Fig. 11 is a fragmentary plan view taken substantially on the line lI-il of Fig. 1 illustrating in detail the connections for supplying electric current to the motor within the housing, and

Fig. 12 is a fragmentary transverse sectional view taken substantially on the line l2-l2 of Fig. 11 illustrating in detail the manner in which the connections are sealed with respect to the wall of the housing, thus maintaining the housing completely closed and fluid tight yet at the same time permitting the introduction of current to supply the-electric motor.

While it will be readily understood from the following description that the relatively specific disclosure shown in the accompanying drawings is provided for the purpose of making clear one specific embodiment of the pump construction which has been found to be extremely satisfactory from a commercial standpoint, it will be readily understood that the specific embodiment disclosed herein is merely illustrative of the generic inventive concept presented and that many and substantial departures therefrom may be made which will fall within the scope of the present invention as defined in the appended claim.

In the embodiment shown in the drawings the pumping unit includes a housing or casing [5, which in the form shown is made from a single integral casting of generally cylindrical conflgu-' ration, closed at the bottom and provided with a plurality of axially disposed webs l6 which extend from the central portion of the bottom across the bottom wall and axially up the sides of the casting and mate at the top with an integrally formed shoulder I'l which serves to provide a'flange for securing a cover in position upon the body of the housing. These webs not only provide an extremely strong structure but serve to make available an extremely large area for the purpose of disseminating heat. The axial central portion of the bottom of the pump casing is provided with a closed axially extending projection l8 forming an internally accessible socket which as will hereinafter be seen serves to provide means for mounting the shaft within the casing and at same time provides an inlet port for the fluid to be pumped. Also preferably integrally formed at the bottom of the casing are bosses i9 and 20 which serveto provide means for mounting the casing upon the base of the apparatus with which it is to be associated.

The housing member is also provided with an aperture or port 22 adjacent the lower side of one of the walls thereof which aperture is internally threaded to receive a conduit (not shown) for conducting the fluid discharged from the pump mechanism.

The upper end of the housing II is adapted to be closed by a cover, preferably formed from a casting 25 which casting has a cylindrical projecwhich annulus is oiled or greased thoroughly prior to its placement within the housing. The" cover 25 is secured in position on the housing by means of an annular series of bolts 29 which pass. through suitable circumferentially spaced apertures in the cover plate 25 and are threadably received by a series of complementally spaced internally threaded recesses provided -in the flange I! of the housing l5. As these screws 29 are set up the rubber annulus 28 will be tightly compressed in order to provide a fluid tight joint between the cover and the housing proper.

Preferably integrally formed on the central portion of the cover 25 is a cylindrical boss 36 which is adapted to receive and closely surround theupper end of a shaft 32 described in detail below. The lower end of this shaft 32'is adapted to be received within the hollow cylindrical socket |8 described above and is locked against rotation therein by means of aset screw 33 threadably received in the wall of the socket l8 and secured in position by means of a lock nut. 34. It will therefore be readily appreciated that the shaft 32 is not only rigidly supported at each of its ends but is locked against rotation and consequently rigidly fixed and supported with respect to the housing within which it is mounted. i

Further it will be readily understood that the mounting of this shaft is such that while it is rigidly supported at both its ends and mounted in such a way that it will not rotate the construction and arrangement of parts is such that the cover may be conveniently removed from the housing and replaced thereon without in any way disturbing the mounting of the shaft 32. This construction greatly facilitates the assembly of the device as a whole and provides an extremely satisfactory mounting for the shaft giving the same complete and adequate support at all times during operation of the apparatus.

- may be removed when it is desired to obtain access to the pumping mechanism located in the lower portion of the casing in the manner described in detail below. This press fitting of the stator 4| within the housing has been found to provide an exceedingly satisfactory and simple method of assembling this element with respect to the casing and one which readily facilitates removal of the parts in order to obtain access to the pump.

The motor also includes an armature 44 rotatably mounted with respectto the field. This armature 44 has a relatively large cylindrical axiallydisposed opening 45 therein, and as whole and provide a bearing upon the vertically dis-' posed stationary shaft 32. k The shaft 32 is preferably formed of hardened steel and the sleeve 46 is preferably a casting in order that a long wearing journal will be provided between these two members. This bearing for the rotary portion of the motor is supplied with lubricant in the manner described in detail below.

The sleeve 46 has an-integrally formed annular flange 48 at :its lower end andhas projecting downwardly therefrom a concentrically disposed pilot 49 upon which is mounted the upper end of a cylinder element 50. The cylinder element is preferably relatively heavy casting with a cylindrical aperture 5| therein concentrically disposed with respect thereto. This cylinder 5| when mounted co-axially with respect to the axis of the shaft 32 surrounds the same. The lower end of the cylinder 5| is closed by means of a cap plate or cover element 55, which is secured thereto by means of an annular series of axially extending cap screws 56, which extend upwardly through the cap member 55 axially through suitable aper tures in the wall of the cylinder member 50, and are threadably received in the flange 48 of the sleeve 46 thus retaining all of these parts in assembled relation.

The cap member 55 is preferably formed of cast iron and has interposedbetween its lower axial end and the casing 50 an annular washer 60, formed of hardened steel thus providing a thrust bearing for the entire rotary assembly.

The portion of the centrally disposed shaft 32 which lies within the. cylinder is enlarged to provide an eccentric 62 which eccentric has a cylindrical external configuration, the axis of which is slightly offset with respect to the axis of the shaft 32 of which this eccentric'62 is an integral part. A valve ring 65 snugly surrounds this eccentric 62 and is sufficient thickness so that one surface of the valve ring will always lie in close engagement with the interior wall of the cylinder 50. The cylinder 50 is cut away to provide a pair of diametrically opposed radially disposed slots 66, which slots extend axially throughout the entire length of the cylinder. to receive vanes 61 and 68 which vanes may be formed of steel and are preferably drilled out to materially decrease the weight thereof. Each of the vanes 61 and 68 has a bracket associated therewith which bracket is of generally U-shaped form and is secured to the cylinder member I by means of screws 1|. Each of the brackets 'lll has a rivet 12 in the outer end thereof which serves to position the outer end of the compression coil spring 13, the inner end of which engages the radially outer end of the vane with which it is associated. It will be clear from the foregoing that these springs confined in this manner serve to constantly urge the vanes .61 and 68 inwardly toward the axis of rotation of the cylinder as a whole. Itv will be readily appreciated that as the cylinder as a whole rotates at relatively high speed the resulting centrifugal force would normally tend to move these vanes outwardly and consequently the springs 13 must be of suflicient strength to overcome this centrifugal force and urge the vanes inwardly towards the axis of rotation of the apparatus at all times.

The inner end of the vane 68 is rounded to provide a semi-cylindrical surface which fits into a complemental semi-cylindrical recess 15 formed in the exterior surface of the valve ring 65. This semi-cylindrical recess 15 extends throughout the entire axial length of the valve ring and it'will be apparent that irrespective of the position of the valve ring the end of the vane will remain seated therein at all times. The inner end of the vane 61 has preferably a flat surface and merely abuts in sealing engagement with the peripheral surfaces of the valve ring 65, thus separating the interior of the cylinder into two separate chambers, the volume of which will be varied as a result of rotation of the cylinder with respect to the shaft 32.

The shaft 32 is bored out at its lower end to provide an axiai duct 80 which extends upwardly from the lower end of the shaft to a point substantialiy in the axial central portion of the eccentric 62 on the shaft. The eccentric portion 62 of the shaft is provided with a circumferentially extending channel or recess Il which extends slightly more than 180 therearound and this recess 11 connects with the axial duct '80 by means of a lateral bore 8I. In order to establish communication between the interior of the cylinder and. the recess 11 a pair of ports 85 are drilled through the valve ring in substantially the axial central portion thereof in such a position that their inner ends communicate with the recess i1 when the valvering is in such a position, that the inner ends of these ports register therewith. Due to the fact that the recess 17 extends only throughout a part of the circumference of the eccentric 62 it will be readily appreciated that communication through the ports 85 will only established at certain predetermined periods during the revolution of the cylinder around the escentric. The lower end of the shaft 32 which seats in the socket I8 has the axially extending duct 80 therein opening out from the axial end of the shaft and communicating with a lateral intake port 90 drilled in the wall of the casing adjacent the lower end of the socket I18 thus establishing communication with the axial bore 80.

A pair of diametrically opposed recesses 9I milled in the exterior wall of the cylinder 50 and suitable exhaust ports 92 are drilled from the base of these recesses radialiy inward through the wall of the cylinder. These ports 92 may be surrounded at their outer end by means of an annular valve seat 93 which may be conveniently formed by a hollow milling cutter fed radially -inwardly and concentrically disposed with respect to the ports 92. 1

These ports are adapted to be controlled by means of flexible valve elements 94 retained in position by means of screws 95 threadably received in the wall of the cylinder and utilized for the purpose of locking the valve members 94 in such a position that these valve members will lightly be disposed on the valve seats 93. valve member 94 is preferably retained in position on the screws 95 by means of a pair of interlecking square washers 95 the exteriors of which fit within the recess 9| to preclude rotation thereof and which have the valve members 94 clamped therebetween, as is clearly illustrated in Fig. '6 of the drawings. It will be readily appreciated from the construction shown that this assembly of interlocking square washers, valve members and screws serve to accurately position the iiexible valve members 90 over the seats 93 of the ex- I haust ports 92.

Further it will be readily understood that the exhaust from the pumping cylinder 50 is discharged into the interior of the casing and inasmuch as the interior of the casing is completely closed, the only escape for the compressed gases will be outwardly through the outlet 22 which sert'es to conduct the compressed gas to the condenser of. the refrigeration system.

In order to insure long life and smooth operation of the apparatus as a whole it is essential that a lubrication system be provided which is in all respects self feeding and serves to maintain an adequate supply of lubricant between all of thebearing surfaces of the apparatus. In order to accomplish this result a pair of axially extend- The ing pores I00 are provided in the wall of the cylinder 50 which bores are preferably located on diametricallyeopposite sides thereof. These bores I00 as is clearly shown in Fig. 8 of the drawings are of preferably enlarged diameter at their lower ends and serve to'receive hoilow dowel members IOI which dowel members are provided with an axial bore i02 therethrough and are closed at their lower ends. These dowels extend a substantial distance downwardly below the lower end of the cylinder construction and sufficiently far down to have their lower ends submerged in a supply of oil normally maintained at a predetermined level in the lower portion of the housing. The dowel members IOI each have a lateral opening I04 adjacent their lower ends which opening communicates with the hollow bore I02 of the dowel members. While the two hollow dowels disposed on each side of the cylinder casing may be of the same length, it has been found preferable to position one of these dowels in such a manner that it extends downward further into the body of oil than the other in order that the path traversed by the lateral opening I04 in one of the dowels will be above or below the path traversed by the other, thus making an adequate supply of oil available to both of the dowels.

The lateral opening in the lower ends of the hoilow dowel members arepreferably positioned so that as rotation of the cylinder member 50 takes place oil will be scooped up by these members and positively forced upwardly through the hollow bores I02 in the dowel members and upwardly through the duct I00 to the upper end of the cylinder construction. Suitable bores I01 are provided in the flange 48 of the sleeve member 46, the bores I 01 registering with the bores Iiiil in the cylinder member. The upper ends of each of the bores I0'I as is clearly seen in Fig. 7 communicates with a tangentially disposed semi-cylindrical duct I08 which in turn communioates with an annular oii distribution recess I09 formed in the upper surface of the flange 48 on the sleeve 46. It will be readily appreciated that the semi-eylindrical duct I08 and the annular oil receiving recess I09 will have the upper sides thereof closed by means of the lower surface of the armature of the motor in which the sleeve 46 is press fitted as has been described above. The tangentially disposed ducts I08 are so positioned that as the cylinder structure as a whole rotates these ducts will serve to; accelerate the flow of oil inwardly toward the axis of rotation of the shaft and in this manner serve to substantially counteract the normal tendency of centrifugal force to effect the flow of this oil in opposite direction.

The oil from the annular oil distribution recess I09 may fiow downwardly through a pair of ducts i I2, clearly seen in Fig. 1, to supply lubricant to the bearing surfaces between the shaft 32 and the sleeve 46. In order to insure a substantially uniform distribution of lubricant throughout the entire axial length of the sleeve 46 the shaft 32 has cut therein a,helically extending groove or duct II; which extends throughout the entire axial length of the sleeve 46 and serves to distribute the oil supplied by the duct I I2 throughout the 4 32, thus insuring uniform distribution of lubricant throughout the bearing surface between the eccentric portion of the shaft 62 and the valve ring 65. In order to further assure proper lubrication'between the bearing of the valve ring on the eccentric portion of the sleeve 62, a helically disposed duct II6 extends up the shaft 32 from a point below the level of oil in the housing. This duct III connects with a helically extending duct II8 on the peripheral surface of the eccentric element 62 and serves to convey oil upwardly from the oil reservoirs in the lower portion of the casing onto the bearing surfaces between the valve ring 65 and eccentric portion 62 of the shaft.

As is clearly seen in Fig. 9, a tangentially disposed port I20 is provided in the cap member 55, the inner end of this port communicates with the lower end of duct H6, and it will be readily appreciated that as the cap member 65 rotates with the cylinder to which it is secured this tangentially disposed port I20 will serve to scoop up oil from the reservoir and positively feed this lubricant upwardly through the ducts H6 and H3, thus insuring a positive supply of lubricant upwardly from the lower axial end of the cylinder.

In order to insure adequate lubrication for the bearing surfaces between the rounded end of the vane 68 and the semi-cylindrical recess I6 in the valve ring it has been found preferable to provide an oil receiving groove I22 in the base of the recess 15 which 011 retaining groove will serve to maintain an adequate supply of oil adjacent these bearing surfaces in order that they will be properly lubricated at all times.

Inasmuch as the housing must at all times be maintained fluid tight it is not only desirable but virtually essential that some permanent and satisfactory means he provided for introducing the leads supplying current to the electric motor through the walls of the housing and establishing a fluid tight connection therebetween at the same time insulating these leads from the metallic wall of the housing. In order toachievethis end the present invention contemplates the provision of the construction substantially illustrated the bolts I32. These washers are preferably.

formed of bakelite or other suitable insulating material. A pair of cylindrical insulating members I36 are disposed around the shanks of the bolts I3I and have prisitioned axially therebetween resilient rubber insulating members I31 which will be tightly compressed as the nuts I33 are" screwed down. The axial compression of this resilient rubber member I31 between the insulating sleeves I36 will serve to. expand the same firmly into contact with 'the walls of the aperture I30 thus effecting a tight seal. It will be readily appreciated that the remainder of the washers serve to effectively insulate all portions of the bolt I3I from the walls of the housing and provide asimple and effective means for introducing the leads to the interior of the housing to connect with the motor. The apparatus may be conveniently assembled in the following manner. The sleeve 46 is first press fitted into the rotor of the electric motor and the shaft 32 is then mounted within the sleeve. The completely-assembled cylinder with its vanes and valves mounted thereon isthen bolted in position upon the sleeve 46 by means of cap screws 56 which as has been explained above further serve the function of retaining the cap member 55in position. The lower'end of the shaft 32 may now be locked against rotation by setting up the set screw 33 and locking the same in position by means of a lock nut 34. The cover plate 25 of the housing'now has the leads from the motor connected thereto and is then seated in position with the boss 30 surrounding the upper end of the shaft 32 in order to accurately position the same centrally with respect to the housing. The cover then may be bolted firmly in position by means of the cap screw 23 thus sealing the housing and the apparatus is ready for installation in a refrigerator system.

The operation of the apparatus is substantially as follows. When the electric current is turned on the rotor 44 of the motor will effect rotation of the sleeve 46 and the cylinder assembly 50 which is connected thereto. This rotation will take place around the stationary centrally disposed shaft 32. In view of the fact that the vane 68 has its inner rounded end seated in the semi-cylindrical recess in the valve ring 65 it will be readily understood that this valve ring will rotate with the cylinder and slide around the eccentric portion 62 of the stationary shaft 32. This movement of the valve ring serves to continually vary the capacity of the chambers formed on the 0pposite sides of the cylinder and will serve to draw fluid upwardly through the duct 80outwardly through the lateral port 8| into the circumferentially extending groove I'I through one of the ports 85 into one of the chambers and expel this fluid through one of the exhaust valves 92 into the housing. Both chambers function substantialy alike and it is noted that the various ports are so positioned that substantially maximum efficiency is obtained. Rotation of the cap member serves to cause the port I20 to scoop up 011 from the supply in the bottom of the casing and feed this oil upwardly through the helically extending duct H6 and duct II8 to maintain the moving parts within the cylinder properly lubricated at all times. Likewise the hollow dowel members serve to feed oil upwardly through the duct I00 into the annular oil distribution duct I03 from whence this oil is fed both downwardly andupwardly along the stationary shaft 32 by means of the helical ducts II3, II and I I5 Consequently it will be readily appreciated that all working surfaces and relatively movable contacting parts within the chamber are supplied with lubricant under pressure at all-times during the operation of the apparatus.

In order to obtain satisfactory operation of the apparatus it is essential that the vanes engage the surface of the valve ring with a light but positive pressure when the apparatus is operating at normal speed. The centrifugal force resulting from 'the rotation of the cylinderconstructionconstantly tends to move these vanes outwardly but it will be readily understood that these vanes are in addition to the inward movement thereof effected by means of the coil springs 13.

While but one specific embodiment of the presv ent invention has been illustrated in the drawings and described above it will be readily understood that this relatively specific disclosure is merely illustrative of the generic inventive features presented in the present application. Many other and further modifications thereof falling within the scope of the invention as defined in the subjoined claim will be clearly apparent to those skilled in the art. 1

What is claimed is:

A pumping unit including in combination an enclosed sealed casing having a centrally d1S posed stationary shaft therein, said shaft having an eccentric portion formed thereon, a valve ring snugly surrounding and rotatably mounted on the eccentric portion of said shaft, an intake port in said shaft having one end opening in the peripheral surface of said eccentric portion and the other end opening in one axial end of said shaft, a cylinder rotatably mounted in said casing on said shaft adapted for rotation coaxially with said shaft, said cylinder surrounding the eccentric portion of said shaft, the walls of said cylinder having slots therein, diametrically disposed radially reciprocable vanes slidably mounted in said slots, resilient means for urging said vanes into engagement with the periphery of said valve ring, one of said vanes having a driving engagement with said valve ring whereby to efiect rotation of said valve ring with said cylinder, the other of said vanes having a sliding engagement with said valve ring, said valve ring having ports therein serving to establish communication between said intake port in said shaft and the interior of said cylinder, said cylinder having exhaust ports in the walls thereof and valves for controlling said exhaust ports.

' GUY C. FRICKE. 

